1. Field of the Invention
The present invention relates to a silent chain including a plurality of link plates arranged in a chain longitudinal direction and a chain width direction and coupled together by coupling pins so as to be bendable.
2. Description of the Related Art
A silent chain is conventionally known in which guide trains each including a lateral pair of guide plates and a middle plate and non-guide-trains each including a plurality of inner plates are alternately coupled together in a chain longitudinal direction by coupling pins, the lateral pair of guide plates each having a longitudinal pair of pin holes, the middle plate being arranged between the guide plates and having a longitudinal pair of pin holes, the inner plates each having a longitudinal pair of pin holes, the coupling pins being inserted into the pin holes (see, for example, Japanese Patent Application Laid-open No. H10-238597).
For such a silent chain, in order to improve the strength of each link plate 120, portions A and B around each pin hole in the link plate 120 as depicted in FIG. 8 can be designed to have large dimensions by adjusting the sizes of peripheral members such as sprockets and chain guides.
However, as depicted in FIG. 8, a portion C positioned in front or back of the pin hole is limited in dimensional design in order to avoid interference between the link plates 120 adjacent to each other in the chain longitudinal direction. In order to improve the strength of the link plate 120 with respect to a chain tensional force, another measure needs to be taken, for example, each link plate 120 needs to be designed to have a large plate thickness. Furthermore, since the portion C positioned in front or back of the pin hole is limited in dimensional design as described above, the dimensional design of the diameters of the pin hole in each link plate 120 and the coupling pin is disadvantageously limited.
Thus, the present invention is intended to solve these problems. An object of the present invention is to provide a silent chain that enhances the degree of design freedom for component dimensions to improve the chain strength with respect to the chain tensile force and that suppresses chain wear elongation.